Previous attempts to incorporate biocidal activity into materials and coatings have primarily involved two methods: (1) physical mixing (blending) of biocides into the materials and coatings, and (2) chemical binding of biocidal functional groups to the polymers or copolymers comprising the materials and coatings. Chemical binding should be preferable for long-term biocidal activity if the bound biocidal functionality does not adversely affect the other desired properties such as strength, appearance, and chemical resistance of the material or coating. For example, a significant amount of work has been performed concerning rendering sponges biocidally active. This involves encapsulation of a variety of weak biocides into the porous structure of the sponge, either through physical blending or chemical bonding to the surface. The sponges modified in this manner can exhibit biocidal activity, but the contact times necessary for action are generally long, and some pathogens are not inactivated even at contact times of several hours. Anti-fouling polyurethanes have been prepared by chemical incorporation of tributyl tin as described in U.S. Pat. No. 5,194,504 and quaternary ammonium salts (see, for example, J. Appl. Polym. Sci. 50:663 (1993) and J. Appl. Polym. Sci. 50:671 (1993)). Coatings containing organo tin compounds are being discredited as threats to the environment, and poly-quats are weak biocides that are non-regenerable. Thus, there is a definite need for more effective biocidal coatings and materials.
A new class of biocidal monomers and polymers known as N-halamines, which could be useful in producing biocidal coatings, has recently been developed. A non-toxic, non-irritating, and cost effective material, poly-1,3-dichloro-5-methyl-5-(4′-vinylphenyl) hydantoin, is an inexpensive derivative of polystyrene, that was first described in U.S. Pat. No. 5,490,983. Subsequent disclosures of its biocidal properties for use in disinfecting applications for water filters have recently occurred (see, for example, Ind. Eng. Chem. Res. 33:168 (1994); Water Res. Bull. 32:793 (1996); Ind. Eng. Chem. Res. 34:4106 (1995); J. Virolog. Meth. 66:263 (1997); Trends in Polym. Sci. 4:364 (1996); Water Cond. & Pur. 39:96 (1997)). The polymer is effective against a broad spectrum of pathogens including Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Candida albicans, Klebsiella terrigena, poliovirus, and rotavirus, among others, causing large log reductions in contact times of the order of a few seconds in water disinfection applications.
N-halamine functional groups such as hydantoins, oxazolidinones, and imidazolidinones have also been employed recently in producing biocidal cellulose (U.S. Pat. No. 5,882,357), biocidal films on surfaces (U.S. Pat. No. 5,902,818), biocidal Nylon (U.S. patent application Ser. No. 09/615,184), and biocidal polyester (U.S. patent application Ser. No. 09/866,535); these patents and patent applications are herein expressly incorporated by reference in their entirety.
U.S. Pat. No. 4,412,078 to Berger describes alkyl and alkoxy silylpropylhydantoin derivatives. Also, silylpropylisocyanurates have been reported for use as adhesive sealants (U.S. Pat. No. 3,821,218. ) Moreover, much work has been done concerning attaching quaternary ammonium functional groups which are weak, non-regenerable biocides to various silicon compounds which can then be bonded to surfaces to render them weakly biocidal (see, for example, U.S. Pat. Nos. 3,560,385; 3,730,701; 3,794,736; 3,814,739; 3,860,709; 4,411,928; 4,282,366; 4,504,541; 4,615,937; 4,692,374; 4,408,996; 4,414,268; and 5,954,869). The N-halamine derivatives of the invention represent a significant improvement in biocidal efficacy over prior art in terms of both the required contact times and increased spectrum of activity.